The Collaborative International Dictionary of English v.0.48:

Dilatory \Dil"a*to*ry\, a. [L. dilatorius, fr. dilator a
   delayer, fr. dilatus, used as p. p. of differe to defer,
   delay: cf. F. dilatoire. See Dilate, Differ, Defer.]
   1. Inclined to defer or put off what ought to be done at
      once; given the procrastination; delaying;
      procrastinating; loitering; as, a dilatory servant.
      [1913 Webster]

   2. Marked by procrastination or delay; tardy; slow; sluggish;
      -- said of actions or measures.
      [1913 Webster]

            Alva, as usual, brought his dilatory policy to bear
            upon his adversary.                   --Motley.
      [1913 Webster]

   Dilatory plea (Law), a plea designed to create delay in the
      trial of a cause, generally founded upon some matter not
      connected with the merits of the case.

   Syn: Slow; delaying; sluggish; inactive; loitering;
        behindhand; backward; procrastinating. See Slow.
        [1913 Webster]

WordNet (r) 3.0 (2006):

dilatory plea
    n 1: a plea that delays the action without settling the cause of
         action; it can challenge the jurisdiction or claim
         disability of the defendant etc. (such defenses are usually
         raised in the defendant's answer)